The present invention relates to a heat appliance and, more particularly, to a switching assembly for a heating appliance which operates in response to the door opening and closing operations of a heating appliance such as a microwave oven.
A conventional switching assembly for a heating appliance is as shown in FIG. 8, and is disclosed in U.S. Pat. No. 4,542,269, entitled "COOKING APPLIANCE WITH SWITCHING ASSEMBLY" by Yasuhiro Sakoda.
Movable latch heads 20 and 21 are, respectively, held by pins 23 and 24, to allow free movement. The latch heads 20 and 21 are connected to a connector lever 25 by pins 26 and 27, respectively. The connector lever 25 is constantly biassed by a spring 28 in the direction of arrow A, and is movable vertically. A door handle 22 is coupled to the latch heads 20 and 21 with pins 29 and 30. When the door handle 22 is pulled in the direction of arrow B, the latch heads 20 and 21 turn counterclockwise around pivot pins 23 and 24. As a result, fingers 31 and 32 at the tips of the latch heads 20 and 21, respectively, moved in the direction of arrow C. Openings 33 and 34 which are provided on the front panel 35, allow the latch heads 20 and 21 to freely enter or leave the space behind the front panel 35. First and second switch base plates 37 and 38 are respectively secured to the upper and lower parts of the bent side wall 36 of the front panel 35. Latch hooks 39 and 40, engageable with the latch heads 20 and 21, are integrally secured to the first and second switch base plates 37 and 38 respectively. When the oven door 2 is closed, the latch heads 39 and 40, respectively, engage the fingers 31 and 32 of the latch heads 20 and 21, thus securely locking the oven door 2 of the microwave oven. The first switch base plate 37 is provided with a first safety switch 41 of a normally open type and a monitor switch 42 of a normally close type. The second switch base plate 38 is provided with a second safety switch 43 of a normally open type. The second safety switch 43 is a control switch and also functions as a heating switch in cooperation with a heating lever or operating lever 44. These switches 41, 42, and 43 are respectively built into the door locking mechanism so that they can be activated in conjunction with the latch heads 20 and 21, respectively. Thus, the monitor switch 42 is under the control of the L-shaped switch lever 45 which is movable by the depressing movement of the point of the latch head 20. A conventional door mechanism is, also, disclosed in U.S. Pat. No. 4,341,409, entitled "DOOR LATCHING ASSEMBLY", by Yasuhiro Sakoda.
In the conventional switching assembly, the L-shaped switching lever is additionally required for switching the first safety switch 41 and the monitor switch 42, thus requiring much labor during assembly, and making it difficult to reduce the cost and make the compact switching assembly.